Grocery stores are probably not the best place to look for pallets since most of the pallets they get must be food safe and therefore expensive. Look for pallets at nurseries or any of the so called dollar stores or other businesses that recieve non edible products in large quantities. Keep in mind that to keep from having these items pile up many of these stores may have a contract with a company that makes mulch to haul them away.

kimmsr and annpat: thank you very much for your quick responses. Correction: I started the wire bin in April 2008. Update: I also have an Earth Machine composter that I put my household refuse in. Every time I dump some refuse in, I top it with about 2 inches of oak leaves. --> I don't think it's ?working? I don't think it's heating up. (I don't have a compost thermometer yet). I don't even see things breaking down. Heck, it was breaking down more/faster when the refuse was in the tupperware container in my kitchen. --> Should I stir it around? I haven't yet (it's been ~5weeks since I started). So this wire bin is only for my insane amount of leaves from all my trees. But I was trying to speed things up a tiny bit, thinking I'll add some green in the middle to heat it up a bit. --> Isn't what I'm doing w/ the green/brown layers kinda like lasagna composting? I think I'll just stop putting greens in there and just keep piling on more browns (dried leaves). thank you very much. Amanda

Plywood would work if it's one single sheet across the entire bottom of the compost bin without one tiny little place for the roots to grow through. Roots will find the tiniest little crack to go through. They will grow upward or sideways, whatever it takes. They like the moisture in the compost pile. Been there, done that. You wouldn't think roots could get into sewer lines either, but they do. I'd go ahead and try it, and then this time next year, if your compost is a root matted mess, you can come up with plan B. I've even had shallow tree roots grow up into the holes of plant pots that were sitting under a tree. Deanna

The idea of the treatment is to preserve the wood. If the wood is still pretty well preserved, I think you have to assume that the treatment chemicals are still in it. I assume you're talking about pressure-treated lumber? If the wood is a few decades old, it might have been CCA treated, and that stuff was pretty nasty. If the only treatment was ten year old stain, it's probably OK to use now for gardening.